While the optical rotation of glyceraldehyde is (+) for R and (−) for S, this is not true for all monosaccharides. The stereochemical rotation can only be determined by the chemical structure, whereas the optical rotation can only be determined empirically (by experiment).

It was by a lucky guess that the molecular d- geometry was assigned to (+)-glyceraldehyde in the late 19th century, as confirmed by X-ray crystallography in 1951.

In the d/l system, glyceraldehyde is used as the configurational standard for carbohydrates. Monosaccharides with an absolute configuration identical to (R)-glyceraldehyde at the last stereocentre, for example C5 in glucose, are assigned the stereo-descriptor d-. Those similar to (S)-glyceraldehyde are assigned an l-.